The 70degree thing is a relic of a issue with the E60 and E90 models that would not regen below 70degrees, of which were very prone to thermostats sticking open. Resulting in clogged DPFs.They were worse were given ‘a run’ as the faster the car went the colder the engine was. I seen these with stuck open ‘stats that would not regen on the motorway but would regen in 25-30mph city driving as the there was less airflow through the radiator...the exact reverse of what the ‘experts’ tell you to do (drive down the motorway).

The ‘F’ model BMWs do not have this issue...they regen pretty much from cold. You will know as the cooling fan kicks in on full pelt with a cold engine and the A/C is turned off (therefore no other reason for the fan to run). As such unless there is a fault or a ash issue, they don’t have any problems.

Ash accumulation and Check engine lights or logged fault codes related to emissions control faults (EGR, oxygen sensor etc.) are the main reasons for DPF issues on the newer BMWs. Indeed, our F07 535d is frequently doing regens (every 50miles or so..should be 300-500miles)...it has a swirl flap position issue (sticking) and has 95K on it. I suspect the swirl flaps are causing it to produce more soot than usual and 90k would usually mean at least 50% of the filter will be full of ash which is impossible to remove, on older cars it could be removed and cleaned, but these ones are part of the catalyst so you can never remove all of the ash as the cat is in the way, regardless of what ‘dpf cleaning’ companies may claim (although loose ash can be blown out, the hardened ‘tubes’ of ash that form in the monolith have no way of being removed).

The fan runs to keep the engine bay cool as during regen the dpf gets up to 600degreeswhich is about twice as hot as normal. If the engine is shut off before completion the fan will carry on running for about five minutes. And yes, the engine has to run for the DPF to ‘clean’ so whatever that service manager was chuntering on about is nonsensical.

The buzzing noises under the bonnet are usually the throttle body, EGR or swirl flap motors staying active, they are servo motors that use pulse width modulation (PWM) to control their speed and positioning, its this PWM that creates fax/modem noises. They should do a short anti-sieze/self check exercise then shut down. You get that on a lot of cars, but they should all be off five minutes after locking the car. I have encountered E60 BMWs that would not ‘sleep’ if he bonnet switch was faulty or not properly clipped in...F07/10/30 BMs don’t have this switch so shouldn’t do this (I think it’s built into the bonnet catch on the later models).


However the hard drive in the sat nav/music storage will run for what seems to be an eternity clicking away behind the dash. Why? Who knows! :cuckoo:

Whenever I’ve looked at aftermarket wheels, I’ve often found the replicas whilst being the same size have different offsets. Sometimes its only a few mm, sometimes more.

Something else I’ve found is diamond cut wheel faces don’t last in this climate...the slightest chip in the laquer results in white worm as soon as the gritters start chucking salt everywhere. Now interestingly I have an old E39 with genuine forged wheels with polished rims and faces, and despite being curbed do not suffer any corrosion. Pity all wheels now are cast.

X-drive seems to be a lottery; My cousin bought a cheap F30 X-drive with over 150k on the clock and its fine. On the other hand I know someone with a same year X3 with just 40k and the transfer box has gone (although I believe that uses a different transfer box to the F30 ).

I’ve looked at how these are built (google ATC 35L), and it’s nothing complex..its just a wet plate lock-up clutch actuated by a servo motor, basically it’s a variable diff-lock. The system “should” fully disengage during normal driving but is able to apply a varying amount of lock proactively (i.e when accelerating hard or if wheel slip is detected). Tyre mismatch should not affect these, but obviously not ideal, but no different to any other full-time AWD car in that respect...you should not stick brand new tyres on one axle with 3mm left on the other axle.

What appears to happen on some of these is the output shaft splines shear off! Now the only way that happens is a massive over-stress (like doughnuts on dry tarmac), corrosion from water ingress, or excessive movement causing the splines to wear down. None of which has anything to do with tyre size or brand...so long as they are all the same size and roughly same wear.

This thread seems to point out the possible real issue at hand in regards to splice failures after finding a brand new case had a loose output shaft! https://f30.bimmerpost.com/forums/sh....php?t=1579087

Aftermarket bodykits are always a matter of personal taste. Some are better than others, but nearly all of them need a good bodyshop to get them to fit...especially fibreglass copies that will require trimming and filling to get the gaps rights and correct any ripples. Better made kits need less prep work, so something like a genuine Alpina or Hartge kit will always be more desirable than some knock-off fibreglass moulding.

I maybe a hypocrit on this as I forgot my Jag has a copied Mk1 Lister bodykit :o